This invention relates to headrests for motor vehicle seats and more particularly to a self-adjusting guide sleeve arrangement for the headrest support posts.
The U.S. Pat. No. 4,854,642 issued Aug. 8, 1989 to Vidwans et al. entitled Head Restraint Guide Assembly discloses a prior art arrangement for adjustably mounting a pair of headrest support posts to a vehicle seat backrest. The Vidwans et al. restraint assembly has a bushing member adapted for retaining and guiding a post supporting the head restraint pad of a motor vehicle seat back. The bushing is installed within the seat back and allows the head restraint pad to be positioned at various vertical positions to suit individual seat occupants. The head restraint post has a plurality of detent notches such that various indexed positions of the head restraint pad are provided. The detent notches of the post have ramped cam surfaces enabling the pad to be moved between the detent positions by exerting axial loads on the post. The retainer notch engages the lug to prevent inadvertent withdrawal of the head restraint pad. Complete withdrawal, however, is provided by an actuator mechanism which urges the lug to withdraw it from engagement with the post retainer notch. The release actuator includes a leaf spring element, having an end which can be depressed downwardly to exert an outward biasing force on the detent lug, causing the lug to be disengaged from the retainer notch enabling the head restraint post to be withdrawn from the head restraint.
Prior art FIGS. 10 and 11 disclose an existing plastic adjustment sleeve assembly 20' for a headrest support post 22' of a vehicle seatback headrest. The sleeve assembly includes an upper radially extending locating flange 24', an intermediate cylindrical engaging upper head 28'. The head portion 26' has a pair of diametrically opposed detent engaging lugs 30' each formed on the free upper end of an integral finger portion 32' projecting vertically upwardly from its associated head portion vertical slot 34'. Each finger portion detent engaging lug 30' is designed for radially inward resilient biased engagement in an associated one of a pair of diametrically opposed complementary shaped V-notches 36' provided in the post 22'.
As best seen in FIG. 10 an annular exterior groove 38' is formed around the upper end of the head portion 26' and the detent lugs 30' so as to capture therein a coiled wire spring 40'. Thus, upon vertical travel of the sleeve assembly 20' on the post 22' the spring 40' allows the pair of lugs 30' to flex radially outwardly from an associated notch 36' for snap-action releasable engagement into a next adjacent vertically aligned post notch (not shown).
The prior art sleeve assembly 20' includes a lower integral spring finger 42' formed with a locking tab 44' adapted to engage the lower edge of a mounting socket (not shown) to prevent inadvertent withdrawal of the sleeve assembly therefrom. The sleeve assembly head portion 26' has a radial shoulder 46' adapted to seat on the upper end of the mounting socket together with a spline 48' adapted to be received in a socket slot (not shown) to prevent relative rotation between the sleeve assembly and the socket.